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Abstract
Male New Zealand White rabbits were made hypercholesterolemic by feeding an atherogenic diet (0.5% cholesterol, 3% peanut oil, and 3% coconut oil) with or without antioxidants. The antioxidant treatments were intravenous injection of $\beta$-carotene (25 mg/kg/BW, twice weekly), dietary $\alpha$-tocopherol (0.5%), and a combination of both. Rabbits treated with $\beta$-carotene had significantly higher plasma and lipoprotein $\beta$-carotene concentrations at 4 and 8 weeks, and significantly lower total and LDL cholesterol concentrations, thoracic atherosclerotic lesion area, and aortic intimal thickness at 8 weeks, but had no effects on TBARS and lag time values compared to control. Rabbits treated with dietary $\alpha$-tocopherol had significantly higher plasma and lipoprotein $\alpha$-tocopherol concentrations and lag time values at 4 and 8 weeks, significantly lower TBARS values at 4 and 8 weeks, and total atherosclerotic lesions and aortic intimal thickness at 8 weeks compared to the control. Rabbits treated with a combination of both antioxidants had significantly higher plasma and lipoprotein $\beta$-carotene and $\alpha$-tocopherol concentrations and lag time values at 4 and 8 weeks, and significantly lower TBARS values at 4 and 8 weeks, as well as significantly lower total atherosclerotic lesion area and aortic intimal thickness at 8 weeks compared to control, but not the $\beta$-carotene or the $\alpha$-tocopherol groups. These data suggest that the antihypercholesterolemic effect of $\beta$-carotene and antioxidant effect of $\alpha$-tocopherol may benefit the rabbits fed an atherogenic diet by inhibiting the development of atherosclerosis.
